Chapter 73 - Asthma

Question 1

What are basic steps of asthma management ED?

Answer 1

1) Assess the severity of the attack
2) Assess potential triggers (eg. animal dander, pollen, mold, respiratory infection, beta blockers, NSAIDs, cigarette smoking, non-adherence)
3) Use inhaled short-acting beta agonists early and frequently, and consider concomitant use of ipratropium for severe exacerbations
4) Start systemic glucocorticoids if there is not an immediate and marked response to the inhaled short-acting beta agonists
5) Make frequent (every one to two hours) objective assessments of the response to therapy until definite, sustained improvement is documented
6) Admit patients who do not respond well after four to six hours to a setting of high surveillance and care
7) Educate patients about the principles of self-management for early recognition and treatment of a recurrent attack and develop an “asthma action plan” for recurrent symptoms

Question 2

What are signs of severe /bad asthma at baseline?

Answer 2

2 major criteria or 1 major + >- 2 minor criteria
Major criteria:
1) treatment with continuous or near continuous oral steroids
2)Requirement for treatment with high dose IV steroids

Minor criteria:

1) additional daily treatment with controlled medication (i.e. LABA)
2) asthma symptoms requiring SABA on a near daily use
3) persistent airway obstruction (FEV1<80%)
4) one or more urgent care visits for asthma per year
5) 3 or more oral steroids bursts per year
6) near fatal asthma event in the past

Question 3

Different causes of wheeze?

Answer 3

valvular heart disease, CHF, COPD exacerbation, pulmonary infection, pneumonia, loffler’s syndrome, chronic eosinophilic pneumonia, upper airway obstruction, laryngeal edema, FB, neoplasm, PE, allergic or anaphylatic reaction, Misc (GERD)

Question 4

Objective findings of severe asthma?

Answer 4

pulse >120 (most severe not >120 always)
RR >40 (not always) 
pulsus paradoxus >10 (50% of pts don't have it ) 
use of accessory muscle for respiration 
abnormal ABG (PaO2 <60, PaCO2 >45)
abnormal PFT

Question 5

Treatment of asthma in ER:

Answer 5

1) Oxygen: titrated >90% or >95% in pregnant woman or known heart disease
2) Short acting Beta Agonist (eg ventolin)
3) Anticholinergics (eg Atrovent or ipratropium)
4) Corticosteroids (eg prednisone or methylprednisilone) – no taper necessary if not pre-existing use or not used for >14days
- 40-80mg of prednisone per day
5) Magnesium sulfate – calcium channel– blocking properties, inhibition of cholinergic neuromuscular transmission, stabilization of mast cells and T lymphocytes, and stimulation of NO and prostacyclin.
- 2-3g over 20 min for severe asthma (FEV1 <25%)

Question 6

What are the intubation and ventilation considerations for to ventilate a critically ill asmatic patient?

Answer 6

1) Delayed RSI: Induction agent: Ketamine/Propofol/Etomidate. No benefit superiority proven yet, but ketamine and propofol have proven bronchodilation. Use Paralysis : succs or roc
2) Vent mode: VC! : control mode as they are paralysed! Volume over pressure limited modes in patients with airflow obstruction issues.
3) Tidal volume 6-8cc/(ideal body weight in kg): lung protective strategy
4) Minute ventilation (respiratory rate multiplied by tidal volume): less than 115 mL/kg/min
5) Allow increased expiratory time by decreasing I:E ratio (1:3 or 1:4 up to 1:5)
6) Low PEEP (start approx 5 or 80% intrinsic PEEP)
7) Start FIO2 at 100 percent then titrate downwards for SpO2 above 90% or PaO2 above 60 mmHg

Question 7

How to determine dispostion from ER for a patient with asthma?

Answer 7

1) Home: good response, FEV1 >70%
2) Hospital admission vs home: 69%40%
3) Critical care unit: FEV1<40% with respiratory failure

Question 8

What’s unique about asthma in pregnancy?

Answer 8

Pregnant women may have high degree of hypercapnia but still normal ABG. Assess patient - if they seem unstable/ hypercapnic - act fast

Pregnant woman have increased O2 demand, decreased FRC, and baseline hyperventilation that is compensated for by a metabolic acidosis. ABGs in pregnancy normally show a pH 7.4-7.45 with a paCO2 of 28-32. So easy to miss the tiring, hypercapnia in pregnancy with a “normal” gas of 7.35 and PCO2 of 35-45. Pay attention to the CLINICAL PICTURE!